Final days for buckthorn control?

For the past several weeks, whenever we can scare up some time from other tasks (such as seed collecting), we have been working on buckthorn control. This is a good time of year to do this, as buckthorn leaves remain green when all other plants have senesced and turned brown. It is really easy to spot the occasional buckthorn plant mixed in with the good plants (see attached photo).

This time of year our method of choice is basal bark treatment with Garlon 4 in bark oil. It is really too late in the year to rely on foliar control, since even though some buckthorn plants still have leaves, many do not. Basal bark treatment works on both kinds of stems.

Our crew has been canvasing all areas where buckthorn is present. With the small stems we must deal with, the preferred method is squirting with a hand spray bottle, which permits precise placement of herbicide. (Depending on the terrain, the sponge stick can also be used.) The various stems in the plant are pulled back, revealing the bare stems at the base. In most cases, all stems can be sprayed at one time, with a couple of squirts. Then on to the next plant.

We previously located major buckthorn patches with the Garmin, and created a map. This helps us considerably in making sure we don't miss any problem areas.

Our buckthorn density is now fairly low, so we can canvas an area fairly quickly. Most of our buckthorn areas are in the western end of the Conservancy, where the bedrock is dolomite (buckthorn is a calciphile).

There are at least three periods of the year when we do buckthorn control.

• Late May after our spring burns, when we use backpack sprayers to treat small buckthorn resprouts with foliar Garlon 3A.
• Mid to late summer. This is the time of year when buckthorn leaves are at their maximum height and the leaf spritz technique works great. Spritzing just two or three of the upper leaves from a hand spray bottle is all that it takes to kill a stem. (See this link for more detail.)
  
• Mid-October to mid-November (now) when we do basal bark with Garlon 4.

Of course, basal bark can be done any time of the year, even winter, although it takes more skill in the winter to find the naked buckthorn stems.

We are determined to eradicate buckthorn from our property. We have made great progress, but I figure it may take another three years to finish the job!